Storage battery



Feb. l1, 1936.. w. l.. REINHARDT STORAGE BATTERY FiledMaroh 9, 1955 Arme/vers mental Feb. 11-, 1936 PATE-NT OFFICE Willard L. Reinhardt, Shaker Heights, Ohio, as-

signor to Willard' Storage Battery Company,d Cleveland, Ohio, a corporation of West Virginia Application March 9, 193s, serial N0. 660,116

8 Claims.

This invention relates to storage batteries of the lead-acid type. and especially to the method of making the plates of such batteries, particularly thenegative plates. 'I'his application is a continuation in part -of my application Serial No. `291,139, filed July 7, 1928.

Ordinarily, the negative plate is made by applying to a framework or grid of antimony lead a paste containing one or more lead oxides which later in the forming or charging operation are converted electrolytically into spongy lead. This spongy lead is metallic lead in very finely divided condition and forms the active material of the negative plate. I

It is common practice to combine with the lead oxide or oxides usedin forming the paste for the negative plate an inert material which performs the function of separating the small particles of nely divided metallic lead, thus preventing them from adhering together and forming larger particles. If this ,inert material, which is commonly called expander, is* not present, relatively large particles of metallic lead will be formed and the active surface of the active material Vwill be re- 25. duced, and this will lessen the capacity and reduce the eiectve life of the negative plate.

Many inert materialshave been used for expanders in forming the paste for negative plates,

such, for example, as barytes, blanc fixe, silica,'

carbon black, lampblack, graphite etc. These materials employed as expanders are practically insoluble in sulphuric acid used in making the' l paste and in the sulphuric acid of the'electrolyte of the nished battery.

In U. S. Patent`No. 1,817,846-, issued in my name, there is described andclaimed an important improvement in expanders which consists in the discovery of a new expander composed chiey of or containing humic acid; Humi'c acid,

' 40 m'addmon to having the properties of Aother expanders as described above, also has vcertain i other distinct advantages, one of which is that it increases'the capacity and life o f the negative pole plate. This -additional capacity produced 415 by humic acid is more pronounced when-the battery is discharged at temperatures below normal than at normal or higher temperatures. While good results are obtained by the use of humic acid inthe manner related in the above patent, I ilnd that, in some instances at least, the best results are obtained by using with the humic acid another expander such as one of vthose previously of the objects of the present invention is (Cl. 13G-27) in the paste or active material and the desired proportion of the expanders..

A further object of the invention is to provide a mode of incorporating the expanders or other useful ingredients in the paste or active material s in a manner such that they will be uniformly distributed throughout the material in finely di-l vided state.

f The single iigure of the drawing is a conventional representation of a battery plate.v w

. In carrying out the invention, for one of the expanders I prefer to employ humic acid because of the fact that it increases the life and capacitye of the negative plate, as explained above. Humic acid may be accompanied by one or more other l5 substances the number and nature of which depend on the source or the manner in which the humic acid is produced. For example, it is possible tio employ either artificial or natural humic substances. An example of an artificial substance is humic acid made by the action of sul: phuric acid on certain carbohydrates. It can be produced in other 'Ways with one or all of which the humic acid may have associated with it somewhat analogous acids, such as ulmic', aprocrenic 25 and crenic acids, which may in themselves have a beneficial eect in the active material, but with the humic acid predominating or constituting the chief ingredient. Examples of natural humic substances are peat and brown coal each of which so 'I believe is composed chiey of humic acid.

'I'herefore, in view of the fact that humic acid may bel accompanied by other materials, when the term humic substance is used, I mean humic acid alone or humic acid associated with one or more other substances with the humic acid preferably predominating.

For the other expander which is to be used with the humic substance, several may be employed. I prefer to use barium sulphate although 40 sulphates of other alkaline earth metals, such as calcium or strontium, may be employed, and doubtless still others are available, but a sulphate of one of the alkaline earth metals, such as barium, is employed not only because it serves well in the lead material as an expander, but because it can be applied along with the humic substance by the precipitation process, as will next be explained. Y

Comingnow to another important part of my invention, I have discovered that, if the two expanders can be precipitated in the lead compound, and particularly if they can be simultaneously preclpitated'from a single solution, they would be uniformly distributed and would be in very' ne condition, as is desirable to obtain the best results. I made the discovery that this 'is possible, and that they can both be precipitated from a single solution, as will now be explained. I might say at this point that it is immaterial Whether the expanders which are in solution and whichare to be precipitated in the lead compound are chemically combined, as for example as a humate of one of the alkaline earth metals, orwhether they are in solution uncombined, as willgbe explained below. It is obvious, therefore, that I may proceed in diierent ways and with diierent materials, but very good results have been obtained by proceeding asfollows:

By treating the humic substance with a suitable solution of an alkaline earth metal, I obtain a solution containing the metal which I believe to be combined with the humic acid as a humate. For example, I may treat the humic substance with a solution of barium hydroxide and obtain what I believe to be barium humate. 'I'his barium humate solution is then incorporated in the paste or active material in any one of several ways hereinafter described, and then by treating the lead material to which the humate has been applied with a suitable reagent, such as sulphuric acid, the two expanders, barium sulphate and humic acid, are simultaneously precipitated, both these substances being insoluble in sulphuric acid. It will be understood, of course, that instead of forming and utilizing for this purpose barium humate, I may form and utilize a humate of other alkaline earthmetals, such ,as those mentioned above.

As stated above, I do not regard it necessary that the solution consist of a humate or of a solution wherein the metal and the humic acid are chemically combined. For example, the artificial or natural humic substance may be dissolved in an alkaline solution and one f the alkaline earth metals, such as barium, calcium, or strontium, may beradded to the same solution as a hydroxide. Whether the dissolved humic substance and the hydroxide of the alkaline earth metal remain as such in solution or whether they combine to form a humate is immaterial to the invention. The remainder of the process is the same whether the solution is obtained in any of the ways above stated, i. e., whether the materials are combined or uncombined.

As before stated, when the solution from which the two expanders are to be precipitated is prepared, I mayA proceed in different ways. I may form the paste by mixing with the lead oxide or oxides the solution from which the expanders are to be later precipitated, and after the solution has been thoroughly, mixed with the oxide or oxides, the expanders may be precipitated in the paste by adding and thoroughly mixing with the paste a mineral acid, such as sulphuric acid. A

part of the sulphuric acid will react with the solution which,.for convenience, will be assumed to be barium humate, forming barium sulphate and humic acid, both ofwhich are precipitated in very nely divided form uniformly throughout the paste. Likewise, if the materials are not combined, the sulphuric acid will react with the hydroxide of the alkaline earth metal forming a sulphate of the metal, and will at the same time kprecipitate humic acid since the latter is insoluble in sulphuric acid. In the latter case, as in the former, the two expanders are precipitated in finely divided condition and uniformly throughout the paste.

It is unnecessary that the sulphuric `acid or other reagent which causes precipitation be added to the paste formed by mixing the lead oxide or oxides with the solution from which the expanders are to be precipitated, but the solution alone may be used with the oxide or oxides to make the paste, and after the mix has been made and the plates have been' pasted, the plates may be dipped into a solutionI of a precipitating reagent, such as sulphuric acid, long enough for the reagent to permeate the paste and cause the precipitation of the two expanders, or the plates thus pasted may be dried without dipping and may then be formed or charged in the usual manner in an electrolyte of sulphuric acid which converts the paste of the negative pole plates into active material or spongy lead. In this operation, the same results are obtained as before. Or the paste may be made without' usingthe solution and later' either the pasted plates or the formed or charged plates may be dipped into the solution until it lhumic acid or substance and the other expander which are thus introduced into the paste or active material by varying the concentration of the humate in solution which is incorporated in the paste or active material or the concentration of the solutions which are mixed-as explained above. It is possible also to vary the ratio of the two expanders for, in making up the solution, it is possible to employ an excess of one or the other of the compounds used in making the solution.

I prefer that the amount of each of the expanders incorporated in the paste or active material in the manner above explained vary from about .1% to about 1% by weight. In the case of the humic substance, I prefer that the humic acid content thereof be within the range stated. I might say that while about equal amounts of the two expanders may in some instances be employed, generally such will not be the case. I may maintain the amount of one expander constant andvary the amount of the other. For ex\ ample, the amount of humic acid thatis employed will generally depend upon the conditions under which the battery is used. Usually the plates of batteries which are discharged at lower temperatures are provided with a greater percentage of humic acid. l

I might add that the expanders are inert, i. e.. they have no deleterious effect on the battery, and, as they are practically insoluble in sulphuric acid, they will remain in the plates and function therein throughout the life of the battery. l

Above I have described my invention as applied' to the production of negative plates. It may also be used in the production of positive plates,v that is to say, it may be used in the lproduction of both the positive and the negative plates, but I now believe it will be suiiicientif the expanders are incorporatedin the negative plates.

In the drawing I have shown conventionally a typical storage batteryplate composed of a grid i0, formed oi leador antimony lead, and the paste or active material l I which contains two aosome expanders which may be incorporated in the paste or active material in any of the ways above mentioned.

' While I have described the introduction of two expanders simultaneously into the paste or into the pores or interstices of the active material, using humic acid as one oi the materials and a sulphate of one of the alkaline earth metals. I do not wish to be confined in so far as certain phases of the invention are concerned, to the use of any of the particular expanders mentioned, and inasmuch as at least one of the expanders mentioned has one or more functions which are different from the function of an ordinary expander, I regard the invention in its broader aspects as covering the introduction into the lead compound of ingredients or materials which have useful functions therein Veven though they 'may not be strictly speaking the function of expanders. I therefore aim in my claims. to cover all modifications which do not involve a departure from the spirit and scope of the invention.

' `The product of the herein described process is claimed in a divisional application Serial`\No. 890,217 nled September'20, 1933.

Having thus described my invention,v I claim:

l. The process which comprises adding to a lead compound for plates of storage batteries of the lead-acid type a humic substance and an alkaline earth metal in solution, and a sulphate which causes the precipitation of humic acid and the sulphate of the alkaline earth metal.

2. The process which comprises` adding to a lead compound for plates of storage batteries of the lead-acid type sulphuric acid, and a humic substance and an alkaline earth metal both in solutiomthereby precipitating in the compound humic acid and the sulphate of the alkaline earth 3. The process which comprises adding to a lead compound for plates of storage batteries of the lead-acid type a solution containing a humic substance andan alkaline earth metal, and an acid sulphate, thereby precipitating in finely divided form humic acid and the sulphate of the alkaline earth metal.

4; The process which comprises adding to a lead compoimd for plates of storage batteries of the lead-'acid type a solution containing a humic substance and an alkaline earth metal, andsulphuric acid, thereby precipitating in the`compoundV in finely divided form humic-acid and the sulphate ofthe alkaline earth metal.

-5. The process of making paste for plates of storage batteries of the lead-acid type which comprises mixing with the lead oxide a solution containing a humic substance and an alkaline earth metal, and sulphuric acid-so as to precipitate in the paste inv finely divided form humic acid and the sulphate of the alkaline earth metal.

6. 'Ihe process in the production of storage battery plates of the lead-acid type which comprises subjecting a lead compound successively lo to the action of a barium-containing solution formed by combining a barium compound with humic acid and to the action of sulphuric acid,

thereby precipitating a barium salt and a humie substance. 7. 'Ihe process in the production of storage battery plates of the lead-acid type which comprises forming the paste containing a lead salt, and subsequently precipitating in the paste a barium salt and a humic substance by bringing together in the paste a barium-containing solution formed by combining a `barium compound with humic acid, and sulphuric acid.

8. The process 1n the production of storagethe active material of a barium salt and a humic substance.

WILIrARD L. REINHARUI. 

